The present invention relates to an automobile seat. More specifically, the present invention relates to a structure of a headrest with which the automobile seat is provided.
For example, a conventional automobile seat is shown in FIGS. 1 to 4. FIG. 1 is a perspective view of a conventional headrest. As shown in FIG. 1, in a headrest 100 in an original state, an X-axis, a Y-axis and a Z-axis are defined in a direction from a rear surface toward a front surface of the headrest 100, a direction from a lower surface toward an upper surface of the headrest 100, and a direction from a left side surface toward a right side surface of the headrest 100, respectively. The X-axis, the Y-axis and the Z-axis are perpendicular to one another. A seat cushion and a seat back holding the seat cushion are not shown because these members are well known.
The headrest 100 comprises a stay 101 and a headrest main body 102. The stay 101 is made of a metal pipe bent into an inverted U-shape. The stay 101 is detachably engaged to the seat back by inserting stay main bodies 103a, 103b (vertical shafts) of the stay 101 into a pair of holders (not shown) which are fixedly installed to a top portion of the seat back (see Japanese Utility Model Publication No. H7-39607). The headrest main body 102 comprises a bracket 106, a pad 108 and a skin 109. The bracket 106 is rotatably attached to a connection section 104 (a horizontal shaft) of the stay 101 because a pair of bearings 107a, 107b installed on one side face of the bracket 106 hold the connection section 104. The pad 108 is made of a urethane foam material and covers the connection section 104, bend sections 105a, 105b of the stay 101 and the bracket 106. The skin 109 is made of a cloth etc. and covers the pad 108 so as to form the headrest main body 102. On the basis of the above structure, the headrest 100 is rotatably fixed to the seat back.
FIG. 2 is a cross-sectional view of the conventional headrest sectioned along a Y-Z plane in FIG. 1. Recesses 110a, 110b are formed on a lower surface of the headrest main body 102 facing the seat back to introduce the stay 101 into an interior of the headrest main body 102. The connection section 104 and the bend sections 105a, 105b of the stay 101 are received in the interior of the headrest main body 102 through the recesses 110a, 110b. Two receiving ports are installed to receive the stay 101 in the interior of the headrest main body 102 from the recesses 110a, 110b. Patches 111a, 111b are installed on the receiving ports so as to prevent a urethane fluid or a semisolid pad existing in the interior of the headrest main body 102 from leaking to an outside of the headrest main body 102 at the time of forming the pad 108. Here, the patches 111a, 111b are fixed to the stay main bodies 103a, 103b at the receiving ports.
FIGS. 3A and 3B are each a cross-sectional view of the conventional headrest sectioned along a SE1-SE1 line in FIG. 2. FIG. 4 is a perspective view of the conventional headrest in which a region C of the head rest shown in FIG. 1 is enlarged. The stay main bodies 103a, 103b of the stay 101 are detachably engaged to the pair of holders that are fixedly installed to the top portion of the seat back. The headrest main body 102 is rotatably attached to the connection section 104 of the stay 101 via the bearings 107a, 107b of the bracket 106. Therefore, the headrest main body 102 may rotate around the connection section 104 in the direction of an arrow shown in FIG. 1.
As shown in FIG. 3A, in a case where the headrest main body 102 is rotated backward by foam pressure of the urethane fluid at the time of forming the pad 108, a gap is generated between the patch 111a and the recess 110a at a left side relative to a center axis M1 of the recess 110a because the patch 111a is fixed to the stay main body 103a. Therefore, the urethane fluid or the semisolid pad may leak to the outside of the headrest main body 102 from the gap. Also, as shown in FIG. 3B, in a case where the headrest main body 102 is rotated frontward by foam pressure of the urethane fluid at the time of forming the pad 108, a gap is generated between the patch 111a and the recess 110a at a right side relative to the center axis M1 of the recess 110a because the patch 111a is fixed to the stay main body 103a. Therefore, the urethane fluid or the semisolid pad may leak to the outside of the headrest main body 102 from the gap. It should be noted that this applies not only to the recess 110a but also to the recess 110b. 
If the urethane fluid or the semisolid pad leaks out, an appearance of the headrest main body 102 becomes ugly because the pad 108 is also generated at the outside of the headrest main body 102, and it takes a lot of effort because it is necessary to remove the pad 108 generated at the outside of the headrest main body 102 by hand. Further, the headrest main body 102 does not smoothly rotate because the gaps between the patch 111a and the recess 110a and between the patch 111b and the recess 110b are filled with the pad 108.
As shown in FIG. 2, in order to dispose the patch 111a between the receiving port of the recess 110a and connection section 104 of the stay 101, it is necessary to increase a length H along the Y-axis of the bend section 105a to some extent. It should be noted that this applies not only to the length H along the Y-axis of the bend section 105a but also to that of the bend section 105b. However, if the length H of the bend sections 105a, 105b increases, an open length L1 of the recesses 110a, 110b must increase so as to secure a predetermined rotational range of the headrest 100 relative to the seat back. Thus, if the open length L1 of the recesses 110a, 110b increases, an area of the receiving port which is not covered by the skin 109 increases with the increment of the open length L1. Thereby, if the headrest main body 102 is rotated frontward or backward by foam pressure of the urethane fluid at the time of forming the pad 108, the urethane fluid or the semisolid pad may widely leak to the outside of the headrest main body 102.
Further, if the length H of the bend sections 105a, 105b has a certain large value, flexibility of a form of the headrest main body 102 is reduced.
The present automobile seat is proposed in view of the above actual conditions. An object of the present automobile seat is to provide an automobile seat comprising a headrest which has high forming-flexibility by lessening the possibility that a urethane fluid or a semisolid pad could leak out of a receiving port for receiving a stay into an interior of the headrest at the time of forming a pad of the headrest and by reducing a gap to be generated between a lower surface of the headrest and a top portion of the stay.